/***************************************************************************/
/*                                                                         */
/*  ftstroke.c                                                             */
/*                                                                         */
/*    FreeType path stroker (body).                                        */
/*                                                                         */
/*  Copyright 2002-2006, 2008-2011 by                                      */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#include <ft2build.h>
#include FT_STROKER_H
#include FT_TRIGONOMETRY_H
#include FT_OUTLINE_H
#include FT_INTERNAL_MEMORY_H
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_OBJECTS_H


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_StrokerBorder )

FT_Outline_GetInsideBorder( FT_Outline

*  outline )
{
FT_Orientation o = FT_Outline_Get_Orientation( outline );


return o == FT_ORIENTATION_TRUETYPE ? FT_STROKER_BORDER_RIGHT
:

FT_STROKER_BORDER_LEFT;

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_StrokerBorder )

FT_Outline_GetOutsideBorder( FT_Outline

*  outline )
{
FT_Orientation o = FT_Outline_Get_Orientation( outline );


return o == FT_ORIENTATION_TRUETYPE ? FT_STROKER_BORDER_LEFT
:

FT_STROKER_BORDER_RIGHT;

}


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****                      BEZIER COMPUTATIONS                      *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/

#define FT_SMALL_CONIC_THRESHOLD  ( FT_ANGLE_PI / 6 )
#define FT_SMALL_CUBIC_THRESHOLD  ( FT_ANGLE_PI / 8 )

#define FT_EPSILON  2

#define FT_IS_SMALL( x )  ( (x) > -FT_EPSILON && (x) < FT_EPSILON )


static FT_Pos
ft_pos_abs( FT_Pos x )
{
    return x >= 0 ? x : -x;
}


static void
ft_conic_split( FT_Vector *base )
{
    FT_Pos a, b;


    base[ 4 ].x = base[ 2 ].x;
    b = base[ 1 ].x;
    a = base[ 3 ].x = ( base[ 2 ].x + b ) / 2;
    b = base[ 1 ].x = ( base[ 0 ].x + b ) / 2;
    base[ 2 ].x = ( a + b ) / 2;

    base[ 4 ].y = base[ 2 ].y;
    b = base[ 1 ].y;
    a = base[ 3 ].y = ( base[ 2 ].y + b ) / 2;
    b = base[ 1 ].y = ( base[ 0 ].y + b ) / 2;
    base[ 2 ].y = ( a + b ) / 2;
}


static FT_Bool
ft_conic_is_small_enough( FT_Vector *base,
                          FT_Angle *angle_in,
                          FT_Angle *angle_out )
{
    FT_Vector d1, d2;
    FT_Angle theta;
    FT_Int close1, close2;


    d1.x = base[ 1 ].x - base[ 2 ].x;
    d1.y = base[ 1 ].y - base[ 2 ].y;
    d2.x = base[ 0 ].x - base[ 1 ].x;
    d2.y = base[ 0 ].y - base[ 1 ].y;

    close1 = FT_IS_SMALL( d1.x ) && FT_IS_SMALL( d1.y );
    close2 = FT_IS_SMALL( d2.x ) && FT_IS_SMALL( d2.y );

    if ( close1 )
    {
        if ( close2 )
        {
            /* basically a point;                      */
            /* do nothing to retain original direction */
        }
        else
        {
            *angle_in =
            *angle_out = FT_Atan2( d2.x, d2.y );
        }
    }
    else /* !close1 */
    {
        if ( close2 )
        {
            *angle_in =
            *angle_out = FT_Atan2( d1.x, d1.y );
        }
        else
        {
            *angle_in = FT_Atan2( d1.x, d1.y );
            *angle_out = FT_Atan2( d2.x, d2.y );
        }
    }

    theta = ft_pos_abs( FT_Angle_Diff( *angle_in, *angle_out ));

    return FT_BOOL( theta < FT_SMALL_CONIC_THRESHOLD);
}


static void
ft_cubic_split( FT_Vector *base )
{
    FT_Pos a, b, c, d;


    base[ 6 ].x = base[ 3 ].x;
    c = base[ 1 ].x;
    d = base[ 2 ].x;
    base[ 1 ].x = a = ( base[ 0 ].x + c ) / 2;
    base[ 5 ].x = b = ( base[ 3 ].x + d ) / 2;
    c = ( c + d ) / 2;
    base[ 2 ].x = a = ( a + c ) / 2;
    base[ 4 ].x = b = ( b + c ) / 2;
    base[ 3 ].x = ( a + b ) / 2;

    base[ 6 ].y = base[ 3 ].y;
    c = base[ 1 ].y;
    d = base[ 2 ].y;
    base[ 1 ].y = a = ( base[ 0 ].y + c ) / 2;
    base[ 5 ].y = b = ( base[ 3 ].y + d ) / 2;
    c = ( c + d ) / 2;
    base[ 2 ].y = a = ( a + c ) / 2;
    base[ 4 ].y = b = ( b + c ) / 2;
    base[ 3 ].y = ( a + b ) / 2;
}


/* Return the average of `angle1' and `angle2'.            */
/* This gives correct result even if `angle1' and `angle2' */
/* have opposite signs.                                    */
static FT_Angle
ft_angle_mean( FT_Angle angle1,
               FT_Angle angle2 )
{
    return angle1 + FT_Angle_Diff( angle1, angle2 ) / 2;
}


static FT_Bool
ft_cubic_is_small_enough( FT_Vector *base,
                          FT_Angle *angle_in,
                          FT_Angle *angle_mid,
                          FT_Angle *angle_out )
{
    FT_Vector d1, d2, d3;
    FT_Angle theta1, theta2;
    FT_Int close1, close2, close3;


    d1.x = base[ 2 ].x - base[ 3 ].x;
    d1.y = base[ 2 ].y - base[ 3 ].y;
    d2.x = base[ 1 ].x - base[ 2 ].x;
    d2.y = base[ 1 ].y - base[ 2 ].y;
    d3.x = base[ 0 ].x - base[ 1 ].x;
    d3.y = base[ 0 ].y - base[ 1 ].y;

    close1 = FT_IS_SMALL( d1.x ) && FT_IS_SMALL( d1.y );
    close2 = FT_IS_SMALL( d2.x ) && FT_IS_SMALL( d2.y );
    close3 = FT_IS_SMALL( d3.x ) && FT_IS_SMALL( d3.y );

    if ( close1 )
    {
        if ( close2 )
        {
            if ( close3 )
            {
                /* basically a point;                      */
                /* do nothing to retain original direction */
            }
            else /* !close3 */
            {
                *angle_in =
                *angle_mid =
                *angle_out = FT_Atan2( d3.x, d3.y );
            }
        }
        else /* !close2 */
        {
            if ( close3 )
            {
                *angle_in =
                *angle_mid =
                *angle_out = FT_Atan2( d2.x, d2.y );
            }
            else /* !close3 */
            {
                *angle_in =
                *angle_mid = FT_Atan2( d2.x, d2.y );
                *angle_out = FT_Atan2( d3.x, d3.y );
            }
        }
    }
    else /* !close1 */
    {
        if ( close2 )
        {
            if ( close3 )
            {
                *angle_in =
                *angle_mid =
                *angle_out = FT_Atan2( d1.x, d1.y );
            }
            else /* !close3 */
            {
                *angle_in = FT_Atan2( d1.x, d1.y );
                *angle_out = FT_Atan2( d3.x, d3.y );
                *angle_mid = ft_angle_mean( *angle_in, *angle_out );
            }
        }
        else /* !close2 */
        {
            if ( close3 )
            {
                *angle_in = FT_Atan2( d1.x, d1.y );
                *angle_mid =
                *angle_out = FT_Atan2( d2.x, d2.y );
            }
            else /* !close3 */
            {
                *angle_in = FT_Atan2( d1.x, d1.y );
                *angle_mid = FT_Atan2( d2.x, d2.y );
                *angle_out = FT_Atan2( d3.x, d3.y );
            }
        }
    }

    theta1 = ft_pos_abs( FT_Angle_Diff( *angle_in, *angle_mid ));
    theta2 = ft_pos_abs( FT_Angle_Diff( *angle_mid, *angle_out ));

    return FT_BOOL( theta1 < FT_SMALL_CUBIC_THRESHOLD &&
                    theta2 < FT_SMALL_CUBIC_THRESHOLD);
}


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****                       STROKE BORDERS                          *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/

typedef enum FT_StrokeTags_
{
    FT_STROKE_TAG_ON = 1,   /* on-curve point  */
    FT_STROKE_TAG_CUBIC = 2,   /* cubic off-point */
    FT_STROKE_TAG_BEGIN = 4,   /* sub-path start  */
    FT_STROKE_TAG_END = 8    /* sub-path end    */

} FT_StrokeTags;

#define  FT_STROKE_TAG_BEGIN_END  ( FT_STROKE_TAG_BEGIN | FT_STROKE_TAG_END )

typedef struct FT_StrokeBorderRec_
{
    FT_UInt num_points;
    FT_UInt max_points;
    FT_Vector *points;
    FT_Byte *tags;
    FT_Bool movable;  /* TRUE for ends of lineto borders */
    FT_Int start;    /* index of current sub-path start point */
    FT_Memory memory;
    FT_Bool valid;

} FT_StrokeBorderRec, *FT_StrokeBorder;


static FT_Error
ft_stroke_border_grow( FT_StrokeBorder border,
                       FT_UInt new_points )
{
    FT_UInt old_max = border->max_points;
    FT_UInt new_max = border->num_points + new_points;
    FT_Error error = FT_Err_Ok;


    if ( new_max > old_max )
    {
        FT_UInt cur_max = old_max;
        FT_Memory memory = border->memory;


        while ( cur_max < new_max )
        {
            cur_max += ( cur_max >> 1 ) + 16;
        }

        if ( FT_RENEW_ARRAY( border->points, old_max, cur_max ) ||
             FT_RENEW_ARRAY( border->tags, old_max, cur_max ))
        {
            goto Exit;
        }

        border->max_points = cur_max;
    }

    Exit:
    return error;
}


static void
ft_stroke_border_close( FT_StrokeBorder border,
                        FT_Bool reverse )
{
    FT_UInt start = border->start;
    FT_UInt count = border->num_points;


    FT_ASSERT( border->start >= 0 );

    /* don't record empty paths! */
    if ( count <= start + 1U )
    {
        border->num_points = start;
    }
    else
    {
        /* copy the last point to the start of this sub-path, since */
        /* it contains the `adjusted' starting coordinates          */
        border->num_points = --count;
        border->points[ start ] = border->points[ count ];

        if ( reverse )
        {
            /* reverse the points */
            {
                FT_Vector *vec1 = border->points + start + 1;
                FT_Vector *vec2 = border->points + count - 1;


                for ( ; vec1 < vec2; vec1++, vec2-- )
                {
                    FT_Vector tmp;


                    tmp = *vec1;
                    *vec1 = *vec2;
                    *vec2 = tmp;
                }
            }

            /* then the tags */
            {
                FT_Byte *tag1 = border->tags + start + 1;
                FT_Byte *tag2 = border->tags + count - 1;


                for ( ; tag1 < tag2; tag1++, tag2-- )
                {
                    FT_Byte tmp;


                    tmp = *tag1;
                    *tag1 = *tag2;
                    *tag2 = tmp;
                }
            }
        }

        border->tags[ start ] |= FT_STROKE_TAG_BEGIN;
        border->tags[ count - 1 ] |= FT_STROKE_TAG_END;
    }

    border->start = -1;
    border->movable = FALSE;
}


static FT_Error
ft_stroke_border_lineto( FT_StrokeBorder border,
                         FT_Vector *to,
                         FT_Bool movable )
{
    FT_Error error = FT_Err_Ok;


    FT_ASSERT( border->start >= 0 );

    if ( border->movable )
    {
        /* move last point */
        border->points[ border->num_points - 1 ] = *to;
    }
    else
    {
        /* don't add zero-length lineto */
        if ( border->num_points > 0 &&
             FT_IS_SMALL( border->points[ border->num_points - 1 ].x - to->x ) &&
             FT_IS_SMALL( border->points[ border->num_points - 1 ].y - to->y ))
        {
            return error;
        }

        /* add one point */
        error = ft_stroke_border_grow( border, 1 );
        if ( !error )
        {
            FT_Vector *vec = border->points + border->num_points;
            FT_Byte *tag = border->tags + border->num_points;


            vec[ 0 ] = *to;
            tag[ 0 ] = FT_STROKE_TAG_ON;

            border->num_points += 1;
        }
    }
    border->movable = movable;
    return error;
}


static FT_Error
ft_stroke_border_conicto( FT_StrokeBorder border,
                          FT_Vector *control,
                          FT_Vector *to )
{
    FT_Error error;


    FT_ASSERT( border->start >= 0 );

    error = ft_stroke_border_grow( border, 2 );
    if ( !error )
    {
        FT_Vector *vec = border->points + border->num_points;
        FT_Byte *tag = border->tags + border->num_points;


        vec[ 0 ] = *control;
        vec[ 1 ] = *to;

        tag[ 0 ] = 0;
        tag[ 1 ] = FT_STROKE_TAG_ON;

        border->num_points += 2;
    }

    border->movable = FALSE;

    return error;
}


static FT_Error
ft_stroke_border_cubicto( FT_StrokeBorder border,
                          FT_Vector *control1,
                          FT_Vector *control2,
                          FT_Vector *to )
{
    FT_Error error;


    FT_ASSERT( border->start >= 0 );

    error = ft_stroke_border_grow( border, 3 );
    if ( !error )
    {
        FT_Vector *vec = border->points + border->num_points;
        FT_Byte *tag = border->tags + border->num_points;


        vec[ 0 ] = *control1;
        vec[ 1 ] = *control2;
        vec[ 2 ] = *to;

        tag[ 0 ] = FT_STROKE_TAG_CUBIC;
        tag[ 1 ] = FT_STROKE_TAG_CUBIC;
        tag[ 2 ] = FT_STROKE_TAG_ON;

        border->num_points += 3;
    }

    border->movable = FALSE;

    return error;
}


#define FT_ARC_CUBIC_ANGLE  ( FT_ANGLE_PI / 2 )


static FT_Error
ft_stroke_border_arcto( FT_StrokeBorder border,
                        FT_Vector *center,
                        FT_Fixed radius,
                        FT_Angle angle_start,
                        FT_Angle angle_diff )
{
    FT_Angle total, angle, step, rotate, next, theta;
    FT_Vector a, b, a2, b2;
    FT_Fixed length;
    FT_Error error = FT_Err_Ok;


    /* compute start point */
    FT_Vector_From_Polar( &a, radius, angle_start );
    a.x += center->x;
    a.y += center->y;

    total = angle_diff;
    angle = angle_start;
    rotate = ( angle_diff >= 0 ) ? FT_ANGLE_PI2 : -FT_ANGLE_PI2;

    while ( total != 0 )
    {
        step = total;
        if ( step > FT_ARC_CUBIC_ANGLE)
        {
            step = FT_ARC_CUBIC_ANGLE;
        }

        else if ( step < -FT_ARC_CUBIC_ANGLE)
        {
            step = -FT_ARC_CUBIC_ANGLE;
        }

        next = angle + step;
        theta = step;
        if ( theta < 0 )
        {
            theta = -theta;
        }

        theta >>= 1;

        /* compute end point */
        FT_Vector_From_Polar( &b, radius, next );
        b.x += center->x;
        b.y += center->y;

        /* compute first and second control points */
        length = FT_MulDiv( radius, FT_Sin( theta ) * 4,
                            ( 0x10000L + FT_Cos( theta )) * 3 );

        FT_Vector_From_Polar( &a2, length, angle + rotate );
        a2.x += a.x;
        a2.y += a.y;

        FT_Vector_From_Polar( &b2, length, next - rotate );
        b2.x += b.x;
        b2.y += b.y;

        /* add cubic arc */
        error = ft_stroke_border_cubicto( border, &a2, &b2, &b );
        if ( error )
        {
            break;
        }

        /* process the rest of the arc ?? */
        a = b;
        total -= step;
        angle = next;
    }

    return error;
}


static FT_Error
ft_stroke_border_moveto( FT_StrokeBorder border,
                         FT_Vector *to )
{
    /* close current open path if any ? */
    if ( border->start >= 0 )
    {
        ft_stroke_border_close( border, FALSE );
    }

    border->start = border->num_points;
    border->movable = FALSE;

    return ft_stroke_border_lineto( border, to, FALSE );
}


static void
ft_stroke_border_init( FT_StrokeBorder border,
                       FT_Memory memory )
{
    border->memory = memory;
    border->points = NULL;
    border->tags = NULL;

    border->num_points = 0;
    border->max_points = 0;
    border->start = -1;
    border->valid = FALSE;
}


static void
ft_stroke_border_reset( FT_StrokeBorder border )
{
    border->num_points = 0;
    border->start = -1;
    border->valid = FALSE;
}


static void
ft_stroke_border_done( FT_StrokeBorder border )
{
    FT_Memory memory = border->memory;


    FT_FREE( border->points );
    FT_FREE( border->tags );

    border->num_points = 0;
    border->max_points = 0;
    border->start = -1;
    border->valid = FALSE;
}


static FT_Error
ft_stroke_border_get_counts( FT_StrokeBorder border,
                             FT_UInt *anum_points,
                             FT_UInt *anum_contours )
{
    FT_Error error = FT_Err_Ok;
    FT_UInt num_points = 0;
    FT_UInt num_contours = 0;

    FT_UInt count = border->num_points;
    FT_Vector *point = border->points;
    FT_Byte *tags = border->tags;
    FT_Int in_contour = 0;


    for ( ; count > 0; count--, num_points++, point++, tags++ )
    {
        if ( tags[ 0 ] & FT_STROKE_TAG_BEGIN )
        {
            if ( in_contour != 0 )
            {
                goto Fail;
            }

            in_contour = 1;
        }
        else if ( in_contour == 0 )
        {
            goto Fail;
        }

        if ( tags[ 0 ] & FT_STROKE_TAG_END )
        {
            in_contour = 0;
            num_contours++;
        }
    }

    if ( in_contour != 0 )
    {
        goto Fail;
    }

    border->valid = TRUE;

    Exit:
    *anum_points = num_points;
    *anum_contours = num_contours;
    return error;

    Fail:
    num_points = 0;
    num_contours = 0;
    goto Exit;
}


static void
ft_stroke_border_export( FT_StrokeBorder border,
                         FT_Outline *outline )
{
    /* copy point locations */
    FT_ARRAY_COPY( outline->points + outline->n_points,
                   border->points,
                   border->num_points );

    /* copy tags */
    {
        FT_UInt count = border->num_points;
        FT_Byte *read = border->tags;
        FT_Byte *write = ( FT_Byte * ) outline->tags + outline->n_points;


        for ( ; count > 0; count--, read++, write++ )
        {
            if ( *read & FT_STROKE_TAG_ON )
            {
                *write = FT_CURVE_TAG_ON;
            }
            else if ( *read & FT_STROKE_TAG_CUBIC )
            {
                *write = FT_CURVE_TAG_CUBIC;
            }
            else
            {
                *write = FT_CURVE_TAG_CONIC;
            }
        }
    }

    /* copy contours */
    {
        FT_UInt count = border->num_points;
        FT_Byte *tags = border->tags;
        FT_Short *write = outline->contours + outline->n_contours;
        FT_Short idx = ( FT_Short ) outline->n_points;


        for ( ; count > 0; count--, tags++, idx++ )
        {
            if ( *tags & FT_STROKE_TAG_END )
            {
                *write++ = idx;
                outline->n_contours++;
            }
        }
    }

    outline->n_points = ( short ) ( outline->n_points + border->num_points );

    FT_ASSERT( FT_Outline_Check( outline ) == 0 );
}


/*************************************************************************/
/*************************************************************************/
/*****                                                               *****/
/*****                           STROKER                             *****/
/*****                                                               *****/
/*************************************************************************/
/*************************************************************************/

#define FT_SIDE_TO_ROTATE( s )   ( FT_ANGLE_PI2 - (s) * FT_ANGLE_PI )

typedef struct FT_StrokerRec_
{
    FT_Angle angle_in;             /* direction into curr join */
    FT_Angle angle_out;            /* direction out of join  */
    FT_Vector center;               /* current position */
    FT_Fixed line_length;          /* length of last lineto */
    FT_Bool first_point;          /* is this the start? */
    FT_Bool subpath_open;         /* is the subpath open? */
    FT_Angle subpath_angle;        /* subpath start direction */
    FT_Vector subpath_start;        /* subpath start position */
    FT_Fixed subpath_line_length;  /* subpath start lineto len */
    FT_Bool handle_wide_strokes;  /* use wide strokes logic? */

    FT_Stroker_LineCap line_cap;
    FT_Stroker_LineJoin line_join;
    FT_Stroker_LineJoin line_join_saved;
    FT_Fixed miter_limit;
    FT_Fixed radius;

    FT_StrokeBorderRec borders[2];
    FT_Library library;

} FT_StrokerRec;


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_Error )

FT_Stroker_New( FT_Library

library,

FT_Stroker *astroker

)
{
FT_Error error;

FT_Memory memory;

FT_Stroker stroker = NULL;


if ( !library )
return

FT_Err_Invalid_Argument;

memory = library->memory;

if ( !

FT_NEW( stroker )

)
{
stroker->

library = library;

ft_stroke_border_init( &stroker->borders[0], memory );
ft_stroke_border_init( &stroker->borders[1], memory );
}

*

astroker = stroker;

return

error;

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( void )

FT_Stroker_Set( FT_Stroker

stroker,

FT_Fixed radius,
        FT_Stroker_LineCap

line_cap,

FT_Stroker_LineJoin line_join,
        FT_Fixed

miter_limit )
{
stroker->

radius = radius;

stroker->

line_cap = line_cap;

stroker->

line_join = line_join;

stroker->

miter_limit = miter_limit;

/* ensure miter limit has sensible value */
if ( stroker->miter_limit < 0x10000 )
stroker->

miter_limit = 0x10000;

/* save line join style:                                           */
/* line join style can be temporarily changed when stroking curves */
stroker->

line_join_saved = line_join;

FT_Stroker_Rewind( stroker );

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( void )

FT_Stroker_Rewind( FT_Stroker

stroker )
{
if ( stroker )
{
ft_stroke_border_reset( &stroker->borders[0] );
ft_stroke_border_reset( &stroker->borders[1] );
}
}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( void )

FT_Stroker_Done( FT_Stroker

stroker )
{
if ( stroker )
{
FT_Memory memory = stroker->library->memory;


ft_stroke_border_done( &stroker->borders[0] );
ft_stroke_border_done( &stroker->borders[1] );

stroker->

library = NULL;

FT_FREE( stroker );

}
}


/* create a circular arc at a corner or cap */
static FT_Error
ft_stroker_arcto( FT_Stroker stroker,
                  FT_Int side )
{
    FT_Angle total, rotate;
    FT_Fixed radius = stroker->radius;
    FT_Error error = FT_Err_Ok;
    FT_StrokeBorder border = stroker->borders + side;


    rotate = FT_SIDE_TO_ROTATE( side );

    total = FT_Angle_Diff( stroker->angle_in, stroker->angle_out );
    if ( total == FT_ANGLE_PI )
    {
        total = -rotate * 2;
    }

    error = ft_stroke_border_arcto( border,
                                    &stroker->center,
                                    radius,
                                    stroker->angle_in + rotate,
                                    total );
    border->movable = FALSE;
    return error;
}


/* add a cap at the end of an opened path */
static FT_Error
ft_stroker_cap( FT_Stroker stroker,
                FT_Angle angle,
                FT_Int side )
{
    FT_Error error = FT_Err_Ok;


    if ( stroker->line_cap == FT_STROKER_LINECAP_ROUND )
    {
        /* add a round cap */
        stroker->angle_in = angle;
        stroker->angle_out = angle + FT_ANGLE_PI;

        error = ft_stroker_arcto( stroker, side );
    }
    else if ( stroker->line_cap == FT_STROKER_LINECAP_SQUARE )
    {
        /* add a square cap */
        FT_Vector delta, delta2;
        FT_Angle rotate = FT_SIDE_TO_ROTATE( side );
        FT_Fixed radius = stroker->radius;
        FT_StrokeBorder border = stroker->borders + side;


        FT_Vector_From_Polar( &delta2, radius, angle + rotate );
        FT_Vector_From_Polar( &delta, radius, angle );

        delta.x += stroker->center.x + delta2.x;
        delta.y += stroker->center.y + delta2.y;

        error = ft_stroke_border_lineto( border, &delta, FALSE );
        if ( error )
        {
            goto Exit;
        }

        FT_Vector_From_Polar( &delta2, radius, angle - rotate );
        FT_Vector_From_Polar( &delta, radius, angle );

        delta.x += delta2.x + stroker->center.x;
        delta.y += delta2.y + stroker->center.y;

        error = ft_stroke_border_lineto( border, &delta, FALSE );
    }
    else if ( stroker->line_cap == FT_STROKER_LINECAP_BUTT )
    {
        /* add a butt ending */
        FT_Vector delta;
        FT_Angle rotate = FT_SIDE_TO_ROTATE( side );
        FT_Fixed radius = stroker->radius;
        FT_StrokeBorder border = stroker->borders + side;


        FT_Vector_From_Polar( &delta, radius, angle + rotate );

        delta.x += stroker->center.x;
        delta.y += stroker->center.y;

        error = ft_stroke_border_lineto( border, &delta, FALSE );
        if ( error )
        {
            goto Exit;
        }

        FT_Vector_From_Polar( &delta, radius, angle - rotate );

        delta.x += stroker->center.x;
        delta.y += stroker->center.y;

        error = ft_stroke_border_lineto( border, &delta, FALSE );
    }

    Exit:
    return error;
}


/* process an inside corner, i.e. compute intersection */
static FT_Error
ft_stroker_inside( FT_Stroker stroker,
                   FT_Int side,
                   FT_Fixed line_length )
{
    FT_StrokeBorder border = stroker->borders + side;
    FT_Angle phi, theta, rotate;
    FT_Fixed length, thcos;
    FT_Vector delta;
    FT_Error error = FT_Err_Ok;
    FT_Bool intersect;          /* use intersection of lines? */


    rotate = FT_SIDE_TO_ROTATE( side );

    theta = FT_Angle_Diff( stroker->angle_in, stroker->angle_out ) / 2;

    /* Only intersect borders if between two lineto's and both */
    /* lines are long enough (line_length is zero for curves). */
    if ( !border->movable || line_length == 0 )
    {
        intersect = FALSE;
    }
    else
    {
        /* compute minimum required length of lines */
        FT_Fixed min_length = ft_pos_abs( FT_MulFix( stroker->radius,
                                                     FT_Tan( theta )));


        intersect = FT_BOOL( stroker->line_length >= min_length &&
                             line_length >= min_length );
    }

    if ( !intersect )
    {
        FT_Vector_From_Polar( &delta, stroker->radius,
                              stroker->angle_out + rotate );
        delta.x += stroker->center.x;
        delta.y += stroker->center.y;

        border->movable = FALSE;
    }
    else
    {
        /* compute median angle */
        phi = stroker->angle_in + theta;

        thcos = FT_Cos( theta );

        length = FT_DivFix( stroker->radius, thcos );

        FT_Vector_From_Polar( &delta, length, phi + rotate );
        delta.x += stroker->center.x;
        delta.y += stroker->center.y;
    }

    error = ft_stroke_border_lineto( border, &delta, FALSE );

    return error;
}


/* process an outside corner, i.e. compute bevel/miter/round */
static FT_Error
ft_stroker_outside( FT_Stroker stroker,
                    FT_Int side,
                    FT_Fixed line_length )
{
    FT_StrokeBorder border = stroker->borders + side;
    FT_Error error;
    FT_Angle rotate;


    if ( stroker->line_join == FT_STROKER_LINEJOIN_ROUND )
    {
        error = ft_stroker_arcto( stroker, side );
    }
    else
    {
        /* this is a mitered (pointed) or beveled (truncated) corner */
        FT_Fixed sigma = 0, radius = stroker->radius;
        FT_Angle theta = 0, phi = 0;
        FT_Fixed thcos = 0;
        FT_Bool bevel, fixed_bevel;


        rotate = FT_SIDE_TO_ROTATE( side );

        bevel =
                FT_BOOL( stroker->line_join == FT_STROKER_LINEJOIN_BEVEL );

        fixed_bevel =
                FT_BOOL( stroker->line_join != FT_STROKER_LINEJOIN_MITER_VARIABLE );

        if ( !bevel )
        {
            theta = FT_Angle_Diff( stroker->angle_in, stroker->angle_out );

            if ( theta == FT_ANGLE_PI )
            {
                theta = rotate;
                phi = stroker->angle_in;
            }
            else
            {
                theta /= 2;
                phi = stroker->angle_in + theta + rotate;
            }

            thcos = FT_Cos( theta );
            sigma = FT_MulFix( stroker->miter_limit, thcos );

            /* is miter limit exceeded? */
            if ( sigma < 0x10000L )
            {
                /* don't create variable bevels for very small deviations; */
                /* FT_Sin(x) = 0 for x <= 57                               */
                if ( fixed_bevel || ft_pos_abs( theta ) > 57 )
                {
                    bevel = TRUE;
                }
            }
        }

        if ( bevel )  /* this is a bevel (broken angle) */
        {
            if ( fixed_bevel )
            {
                /* the outer corners are simply joined together */
                FT_Vector delta;


                /* add bevel */
                FT_Vector_From_Polar( &delta,
                                      radius,
                                      stroker->angle_out + rotate );
                delta.x += stroker->center.x;
                delta.y += stroker->center.y;

                border->movable = FALSE;
                error = ft_stroke_border_lineto( border, &delta, FALSE );
            }
            else /* variable bevel */
            {
                /* the miter is truncated */
                FT_Vector middle, delta;
                FT_Fixed length;


                /* compute middle point */
                FT_Vector_From_Polar( &middle,
                                      FT_MulFix( radius, stroker->miter_limit ),
                                      phi );
                middle.x += stroker->center.x;
                middle.y += stroker->center.y;

                /* compute first angle point */
                length = FT_MulFix( radius,
                                    FT_DivFix( 0x10000L - sigma,
                                               ft_pos_abs( FT_Sin( theta ))));

                FT_Vector_From_Polar( &delta, length, phi + rotate );
                delta.x += middle.x;
                delta.y += middle.y;

                error = ft_stroke_border_lineto( border, &delta, FALSE );
                if ( error )
                {
                    goto Exit;
                }

                /* compute second angle point */
                FT_Vector_From_Polar( &delta, length, phi - rotate );
                delta.x += middle.x;
                delta.y += middle.y;

                error = ft_stroke_border_lineto( border, &delta, FALSE );
                if ( error )
                {
                    goto Exit;
                }

                /* finally, add an end point; only needed if not lineto */
                /* (line_length is zero for curves)                     */
                if ( line_length == 0 )
                {
                    FT_Vector_From_Polar( &delta,
                                          radius,
                                          stroker->angle_out + rotate );

                    delta.x += stroker->center.x;
                    delta.y += stroker->center.y;

                    error = ft_stroke_border_lineto( border, &delta, FALSE );
                }
            }
        }
        else /* this is a miter (intersection) */
        {
            FT_Fixed length;
            FT_Vector delta;


            length = FT_DivFix( stroker->radius, thcos );

            FT_Vector_From_Polar( &delta, length, phi );
            delta.x += stroker->center.x;
            delta.y += stroker->center.y;

            error = ft_stroke_border_lineto( border, &delta, FALSE );
            if ( error )
            {
                goto Exit;
            }

            /* now add an end point; only needed if not lineto */
            /* (line_length is zero for curves)                */
            if ( line_length == 0 )
            {
                FT_Vector_From_Polar( &delta,
                                      stroker->radius,
                                      stroker->angle_out + rotate );
                delta.x += stroker->center.x;
                delta.y += stroker->center.y;

                error = ft_stroke_border_lineto( border, &delta, FALSE );
            }
        }
    }

    Exit:
    return error;
}


static FT_Error
ft_stroker_process_corner( FT_Stroker stroker,
                           FT_Fixed line_length )
{
    FT_Error error = FT_Err_Ok;
    FT_Angle turn;
    FT_Int inside_side;


    turn = FT_Angle_Diff( stroker->angle_in, stroker->angle_out );

    /* no specific corner processing is required if the turn is 0 */
    if ( turn == 0 )
    {
        goto Exit;
    }

    /* when we turn to the right, the inside side is 0 */
    inside_side = 0;

    /* otherwise, the inside side is 1 */
    if ( turn < 0 )
    {
        inside_side = 1;
    }

    /* process the inside side */
    error = ft_stroker_inside( stroker, inside_side, line_length );
    if ( error )
    {
        goto Exit;
    }

    /* process the outside side */
    error = ft_stroker_outside( stroker, 1 - inside_side, line_length );

    Exit:
    return error;
}


/* add two points to the left and right borders corresponding to the */
/* start of the subpath                                              */
static FT_Error
ft_stroker_subpath_start( FT_Stroker stroker,
                          FT_Angle start_angle,
                          FT_Fixed line_length )
{
    FT_Vector delta;
    FT_Vector point;
    FT_Error error;
    FT_StrokeBorder border;


    FT_Vector_From_Polar( &delta, stroker->radius,
                          start_angle + FT_ANGLE_PI2 );

    point.x = stroker->center.x + delta.x;
    point.y = stroker->center.y + delta.y;

    border = stroker->borders;
    error = ft_stroke_border_moveto( border, &point );
    if ( error )
    {
        goto Exit;
    }

    point.x = stroker->center.x - delta.x;
    point.y = stroker->center.y - delta.y;

    border++;
    error = ft_stroke_border_moveto( border, &point );

    /* save angle, position, and line length for last join */
    /* (line_length is zero for curves)                    */
    stroker->subpath_angle = start_angle;
    stroker->first_point = FALSE;
    stroker->subpath_line_length = line_length;

    Exit:
    return error;
}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_Error )

FT_Stroker_LineTo( FT_Stroker

stroker,

FT_Vector *to

)
{
FT_Error error = FT_Err_Ok;

FT_StrokeBorder border;

FT_Vector delta;

FT_Angle angle;

FT_Int side;

FT_Fixed line_length;


delta.

x = to->x - stroker->center.x;

delta.

y = to->y - stroker->center.y;

/* a zero-length lineto is a no-op; avoid creating a spurious corner */
if ( delta.x == 0 && delta.y == 0 )
goto

Exit;

/* compute length of line */
line_length = FT_Vector_Length( &delta );

angle = FT_Atan2( delta.x, delta.y );

FT_Vector_From_Polar( &delta, stroker->radius, angle + FT_ANGLE_PI2 );

/* process corner if necessary */
if ( stroker->first_point )
{
/* This is the first segment of a subpath.  We need to     */
/* add a point to each border at their respective starting */
/* point locations.                                        */
error = ft_stroker_subpath_start( stroker, angle, line_length );

if ( error )
goto

Exit;

}
else
{
/* process the current corner */
stroker->

angle_out = angle;

error = ft_stroker_process_corner( stroker, line_length );

if ( error )
goto

Exit;

}

/* now add a line segment to both the `inside' and `outside' paths */
for (

border = stroker->borders, side = 1;

side >= 0; side--, border++ )
{
FT_Vector point;


point.

x = to->x + delta.x;

point.

y = to->y + delta.y;

/* the ends of lineto borders are movable */
error = ft_stroke_border_lineto( border, &point, TRUE );

if ( error )
goto

Exit;

delta.

x = -delta.x;

delta.

y = -delta.y;

}

stroker->

angle_in = angle;

stroker->

center = *to;

stroker->

line_length = line_length;

Exit:
return

error;

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_Error )

FT_Stroker_ConicTo( FT_Stroker

stroker,

FT_Vector *control,
        FT_Vector

*  to )
{
FT_Error error = FT_Err_Ok;

FT_Vector bez_stack[34];

FT_Vector *arc;

FT_Vector *limit = bez_stack + 30;

FT_Bool first_arc = TRUE;


/* if all control points are coincident, this is a no-op; */
/* avoid creating a spurious corner                       */
if ( FT_IS_SMALL( stroker->center.x - control->x ) &&
FT_IS_SMALL( stroker->center.y - control->y ) &&
FT_IS_SMALL( control->x - to->x ) &&
FT_IS_SMALL( control->y - to->y ))
{
stroker->

center = *to;

goto

Exit;

}

arc = bez_stack;

arc[0] = *

to;

arc[1] = *

control;

arc[2] = stroker->

center;

while ( arc >= bez_stack )
{
FT_Angle angle_in, angle_out;


/* initialize with current direction */
angle_in = angle_out = stroker->angle_in;

if ( arc < limit                                             &&
!

ft_conic_is_small_enough( arc,

&angle_in, &angle_out ))
{
if ( stroker->first_point )
stroker->

angle_in = angle_in;

ft_conic_split( arc );

arc += 2;
continue;
}

if ( first_arc )
{
first_arc = FALSE;

/* process corner if necessary */
if ( stroker->first_point )

error = ft_stroker_subpath_start( stroker, angle_in, 0 );

else
{
stroker->

angle_out = angle_in;

error = ft_stroker_process_corner( stroker, 0 );

}
}
else if (

ft_pos_abs ( FT_Angle_Diff( stroker

->angle_in, angle_in )) >
FT_SMALL_CONIC_THRESHOLD / 4                             )
{
/* if the deviation from one arc to the next is too great, */
/* add a round corner                                      */
stroker->

center = arc[ 2 ];

stroker->

angle_out = angle_in;

stroker->

line_join = FT_STROKER_LINEJOIN_ROUND;

error = ft_stroker_process_corner( stroker, 0 );

/* reinstate line join style */
stroker->

line_join = stroker->line_join_saved;

}

if ( error )
goto

Exit;

/* the arc's angle is small enough; we can add it directly to each */
/* border                                                          */
{
FT_Vector ctrl, end;

FT_Angle theta, phi, rotate, alpha0 = 0;

FT_Fixed length;

FT_StrokeBorder border;

FT_Int side;


theta = FT_Angle_Diff( angle_in, angle_out ) / 2;

phi = angle_in + theta;

length = FT_DivFix( stroker->radius, FT_Cos( theta ));

/* compute direction of original arc */
if ( stroker->handle_wide_strokes )

alpha0 = FT_Atan2( arc[ 0 ].x - arc[ 2 ].x, arc[ 0 ].y - arc[ 2 ].y );

for (

border = stroker->borders, side = 0;

side <= 1;
side++, border++ )
{
rotate = FT_SIDE_TO_ROTATE( side );

/* compute control point */
FT_Vector_From_Polar( &ctrl, length, phi + rotate );
ctrl.x += arc[1].

x;

ctrl.y += arc[1].

y;

/* compute end point */
FT_Vector_From_Polar( &end, stroker->radius, angle_out + rotate );
end.x += arc[0].

x;

end.y += arc[0].

y;

if ( stroker->handle_wide_strokes )
{
FT_Vector start;

FT_Angle alpha1;


/* determine whether the border radius is greater than the */
/* radius of curvature of the original arc                 */
start = border->points[ border->num_points - 1 ];

alpha1 = FT_Atan2( end.x - start.x, end.y - start.y );

/* is the direction of the border arc opposite to */
/* that of the original arc? */
if (

ft_pos_abs ( FT_Angle_Diff( alpha0, alpha1 ))

>
FT_ANGLE_PI / 2                             )
{
FT_Angle beta, gamma;

FT_Vector bvec, delta;

FT_Fixed blen, sinA, sinB, alen;


/* use the sine rule to find the intersection point */
beta = FT_Atan2( arc[ 2 ].x - start.x, arc[ 2 ].y - start.y );

gamma = FT_Atan2( arc[ 0 ].x - end.x, arc[ 0 ].y - end.y );

bvec.

x = end.x - start.x;

bvec.

y = end.y - start.y;

blen = FT_Vector_Length( &bvec );

sinA = ft_pos_abs( FT_Sin( alpha1 - gamma ));

sinB = ft_pos_abs( FT_Sin( beta - gamma ));

alen = FT_DivFix( FT_MulFix( blen, sinA ), sinB );

FT_Vector_From_Polar( &delta, alen, beta );
delta.x += start.

x;

delta.y += start.

y;

/* circumnavigate the negative sector backwards */
border->

movable = FALSE;

error = ft_stroke_border_lineto( border, &delta, FALSE );

if ( error )
goto

Exit;

error = ft_stroke_border_lineto( border, &end, FALSE );

if ( error )
goto

Exit;

error = ft_stroke_border_conicto( border, &ctrl, &start );

if ( error )
goto

Exit;

/* and then move to the endpoint */
error = ft_stroke_border_lineto( border, &end, FALSE );

if ( error )
goto

Exit;

continue;
}

/* else fall through */
}

/* simply add an arc */
error = ft_stroke_border_conicto( border, &ctrl, &end );

if ( error )
goto

Exit;

}
}

arc -= 2;

stroker->

angle_in = angle_out;

}

stroker->

center = *to;

Exit:
return

error;

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_Error )

FT_Stroker_CubicTo( FT_Stroker

stroker,

FT_Vector *control1,
        FT_Vector

*  control2,

FT_Vector *to

)
{
FT_Error error = FT_Err_Ok;

FT_Vector bez_stack[37];

FT_Vector *arc;

FT_Vector *limit = bez_stack + 32;

FT_Bool first_arc = TRUE;


/* if all control points are coincident, this is a no-op; */
/* avoid creating a spurious corner */
if ( FT_IS_SMALL( stroker->center.x - control1->x ) &&
FT_IS_SMALL( stroker->center.y - control1->y ) &&
FT_IS_SMALL( control1->x - control2->x ) &&
FT_IS_SMALL( control1->y - control2->y ) &&
FT_IS_SMALL( control2->x - to->x ) &&
FT_IS_SMALL( control2->y - to->y ))
{
stroker->

center = *to;

goto

Exit;

}

arc = bez_stack;

arc[0] = *

to;

arc[1] = *

control2;

arc[2] = *

control1;

arc[3] = stroker->

center;

while ( arc >= bez_stack )
{
FT_Angle angle_in, angle_mid, angle_out;


/* initialize with current direction */
angle_in = angle_out = angle_mid = stroker->angle_in;

if ( arc < limit                                         &&
!

ft_cubic_is_small_enough( arc,

&angle_in,
&angle_mid, &angle_out ))
{
if ( stroker->first_point )
stroker->

angle_in = angle_in;

ft_cubic_split( arc );

arc += 3;
continue;
}

if ( first_arc )
{
first_arc = FALSE;

/* process corner if necessary */
if ( stroker->first_point )

error = ft_stroker_subpath_start( stroker, angle_in, 0 );

else
{
stroker->

angle_out = angle_in;

error = ft_stroker_process_corner( stroker, 0 );

}
}
else if (

ft_pos_abs ( FT_Angle_Diff( stroker

->angle_in, angle_in )) >
FT_SMALL_CUBIC_THRESHOLD / 4                             )
{
/* if the deviation from one arc to the next is too great, */
/* add a round corner                                      */
stroker->

center = arc[ 3 ];

stroker->

angle_out = angle_in;

stroker->

line_join = FT_STROKER_LINEJOIN_ROUND;

error = ft_stroker_process_corner( stroker, 0 );

/* reinstate line join style */
stroker->

line_join = stroker->line_join_saved;

}

if ( error )
goto

Exit;

/* the arc's angle is small enough; we can add it directly to each */
/* border                                                          */
{
FT_Vector ctrl1, ctrl2, end;

FT_Angle theta1, phi1, theta2, phi2, rotate, alpha0 = 0;

FT_Fixed length1, length2;

FT_StrokeBorder border;

FT_Int side;


theta1 = FT_Angle_Diff( angle_in, angle_mid ) / 2;

theta2 = FT_Angle_Diff( angle_mid, angle_out ) / 2;

phi1 = ft_angle_mean( angle_in, angle_mid );

phi2 = ft_angle_mean( angle_mid, angle_out );

length1 = FT_DivFix( stroker->radius, FT_Cos( theta1 ));

length2 = FT_DivFix( stroker->radius, FT_Cos( theta2 ));

/* compute direction of original arc */
if ( stroker->handle_wide_strokes )

alpha0 = FT_Atan2( arc[ 0 ].x - arc[ 3 ].x, arc[ 0 ].y - arc[ 3 ].y );

for (

border = stroker->borders, side = 0;

side <= 1;
side++, border++ )
{
rotate = FT_SIDE_TO_ROTATE( side );

/* compute control points */
FT_Vector_From_Polar( &ctrl1, length1, phi1 + rotate );
ctrl1.x += arc[2].

x;

ctrl1.y += arc[2].

y;

FT_Vector_From_Polar( &ctrl2, length2, phi2 + rotate );
ctrl2.x += arc[1].

x;

ctrl2.y += arc[1].

y;

/* compute end point */
FT_Vector_From_Polar( &end, stroker->radius, angle_out + rotate );
end.x += arc[0].

x;

end.y += arc[0].

y;

if ( stroker->handle_wide_strokes )
{
FT_Vector start;

FT_Angle alpha1;


/* determine whether the border radius is greater than the */
/* radius of curvature of the original arc                 */
start = border->points[ border->num_points - 1 ];

alpha1 = FT_Atan2( end.x - start.x, end.y - start.y );

/* is the direction of the border arc opposite to */
/* that of the original arc? */
if (

ft_pos_abs ( FT_Angle_Diff( alpha0, alpha1 ))

>
FT_ANGLE_PI / 2                             )
{
FT_Angle beta, gamma;

FT_Vector bvec, delta;

FT_Fixed blen, sinA, sinB, alen;


/* use the sine rule to find the intersection point */
beta = FT_Atan2( arc[ 3 ].x - start.x, arc[ 3 ].y - start.y );

gamma = FT_Atan2( arc[ 0 ].x - end.x, arc[ 0 ].y - end.y );

bvec.

x = end.x - start.x;

bvec.

y = end.y - start.y;

blen = FT_Vector_Length( &bvec );

sinA = ft_pos_abs( FT_Sin( alpha1 - gamma ));

sinB = ft_pos_abs( FT_Sin( beta - gamma ));

alen = FT_DivFix( FT_MulFix( blen, sinA ), sinB );

FT_Vector_From_Polar( &delta, alen, beta );
delta.x += start.

x;

delta.y += start.

y;

/* circumnavigate the negative sector backwards */
border->

movable = FALSE;

error = ft_stroke_border_lineto( border, &delta, FALSE );

if ( error )
goto

Exit;

error = ft_stroke_border_lineto( border, &end, FALSE );

if ( error )
goto

Exit;

error = ft_stroke_border_cubicto( border,
                                  &ctrl2,
                                  &ctrl1,
                                  &start );

if ( error )
goto

Exit;

/* and then move to the endpoint */
error = ft_stroke_border_lineto( border, &end, FALSE );

if ( error )
goto

Exit;

continue;
}

/* else fall through */
}

/* simply add an arc */
error = ft_stroke_border_cubicto( border, &ctrl1, &ctrl2, &end );

if ( error )
goto

Exit;

}
}

arc -= 3;

stroker->

angle_in = angle_out;

}

stroker->

center = *to;

Exit:
return

error;

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_Error )

FT_Stroker_BeginSubPath( FT_Stroker

stroker,

FT_Vector *to,
        FT_Bool

open )
{
/* We cannot process the first point, because there is not enough      */
/* information regarding its corner/cap.  The latter will be processed */
/* in the `FT_Stroker_EndSubPath' routine.                             */
/*                                                                     */
stroker->

first_point = TRUE;

stroker->

center = *to;

stroker->

subpath_open = open;

/* Determine if we need to check whether the border radius is greater */
/* than the radius of curvature of a curve, to handle this case       */
/* specially.  This is only required if bevel joins or butt caps may  */
/* be created, because round & miter joins and round & square caps    */
/* cover the negative sector created with wide strokes.               */
stroker->

handle_wide_strokes =
FT_BOOL( stroker->line_join != FT_STROKER_LINEJOIN_ROUND ||
         ( stroker->subpath_open &&
           stroker->line_cap == FT_STROKER_LINECAP_BUTT ));

/* record the subpath start point for each border */
stroker->

subpath_start = *to;

stroker->

angle_in = 0;

return

FT_Err_Ok;

}


static FT_Error
ft_stroker_add_reverse_left( FT_Stroker stroker,
                             FT_Bool open )
{
    FT_StrokeBorder right = stroker->borders + 0;
    FT_StrokeBorder left = stroker->borders + 1;
    FT_Int new_points;
    FT_Error error = FT_Err_Ok;


    FT_ASSERT( left->start >= 0 );

    new_points = left->num_points - left->start;
    if ( new_points > 0 )
    {
        error = ft_stroke_border_grow( right, ( FT_UInt ) new_points );
        if ( error )
        {
            goto Exit;
        }

        {
            FT_Vector * dst_point = right->points + right->num_points;
            FT_Byte *dst_tag = right->tags + right->num_points;
            FT_Vector * src_point = left->points + left->num_points - 1;
            FT_Byte *src_tag = left->tags + left->num_points - 1;


            while ( src_point >= left->points + left->start )
            {
                *dst_point = *src_point;
                *dst_tag = *src_tag;

                if ( open )
                {
                    dst_tag[ 0 ] &= ~FT_STROKE_TAG_BEGIN_END;
                }
                else
                {
                    FT_Byte ttag =
                            ( FT_Byte )( dst_tag[ 0 ] & FT_STROKE_TAG_BEGIN_END);


                    /* switch begin/end tags if necessary */
                    if ( ttag == FT_STROKE_TAG_BEGIN ||
                         ttag == FT_STROKE_TAG_END )
                    {
                        dst_tag[ 0 ] ^= FT_STROKE_TAG_BEGIN_END;
                    }
                }

                src_point--;
                src_tag--;
                dst_point++;
                dst_tag++;
            }
        }

        left->num_points = left->start;
        right->num_points += new_points;

        right->movable = FALSE;
        left->movable = FALSE;
    }

    Exit:
    return error;
}


/* documentation is in ftstroke.h */

/* there's a lot of magic in this function! */
FT_EXPORT_DEF( FT_Error )

FT_Stroker_EndSubPath( FT_Stroker

stroker )
{
FT_Error error = FT_Err_Ok;


if ( stroker->subpath_open )
{
FT_StrokeBorder right = stroker->borders;


/* All right, this is an opened path, we need to add a cap between */
/* right & left, add the reverse of left, then add a final cap     */
/* between left & right.                                           */
error = ft_stroker_cap( stroker, stroker->angle_in, 0 );

if ( error )
goto

Exit;

/* add reversed points from `left' to `right' */
error = ft_stroker_add_reverse_left( stroker, TRUE );

if ( error )
goto

Exit;

/* now add the final cap */
stroker->

center = stroker->subpath_start;

error = ft_stroker_cap( stroker,
                        stroker->subpath_angle + FT_ANGLE_PI, 0 );

if ( error )
goto

Exit;

/* Now end the right subpath accordingly.  The left one is */
/* rewind and doesn't need further processing.             */
ft_stroke_border_close( right, FALSE

);
}
else
{
FT_Angle turn;

FT_Int inside_side;


/* close the path if needed */
if ( stroker->center.x != stroker->subpath_start.x ||
stroker->center.y != stroker->subpath_start.y )
{
error = FT_Stroker_LineTo( stroker, &stroker->subpath_start );

if ( error )
goto

Exit;

}

/* process the corner */
stroker->

angle_out = stroker->subpath_angle;

turn = FT_Angle_Diff( stroker->angle_in,
                      stroker->angle_out );

/* no specific corner processing is required if the turn is 0 */
if ( turn != 0 )
{
/* when we turn to the right, the inside side is 0 */
inside_side = 0;

/* otherwise, the inside side is 1 */
if ( turn < 0 )

inside_side = 1;

error = ft_stroker_inside( stroker,
                           inside_side,
                           stroker->subpath_line_length );

if ( error )
goto

Exit;

/* process the outside side */
error = ft_stroker_outside( stroker,
                            1 - inside_side,
                            stroker->subpath_line_length );

if ( error )
goto

Exit;

}

/* then end our two subpaths */
ft_stroke_border_close( stroker

->borders + 0, FALSE );

ft_stroke_border_close( stroker

->borders + 1, TRUE );
}

Exit:
return

error;

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_Error )

FT_Stroker_GetBorderCounts( FT_Stroker

stroker,

FT_StrokerBorder border,
        FT_UInt

*anum_points,

FT_UInt *anum_contours

)
{
FT_UInt num_points = 0, num_contours = 0;

FT_Error error;


if ( !stroker || border > 1 )
{
error = FT_Err_Invalid_Argument;

goto

Exit;

}

error = ft_stroke_border_get_counts( stroker->borders + border,
                                     &num_points, &num_contours );

Exit:
if ( anum_points )
*

anum_points = num_points;

if ( anum_contours )
*

anum_contours = num_contours;

return

error;

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_Error )

FT_Stroker_GetCounts( FT_Stroker

stroker,

FT_UInt *anum_points,
        FT_UInt

*anum_contours )
{
FT_UInt count1, count2, num_points = 0;

FT_UInt count3, count4, num_contours = 0;

FT_Error error;


error = ft_stroke_border_get_counts( stroker->borders + 0,
                                     &count1, &count2 );

if ( error )
goto

Exit;

error = ft_stroke_border_get_counts( stroker->borders + 1,
                                     &count3, &count4 );

if ( error )
goto

Exit;

num_points = count1 + count3;

num_contours = count2 + count4;

Exit:
*

anum_points = num_points;

*

anum_contours = num_contours;

return

error;

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( void )

FT_Stroker_ExportBorder( FT_Stroker

stroker,

FT_StrokerBorder border,
        FT_Outline

*       outline )
{
if ( border == FT_STROKER_BORDER_LEFT  ||
border == FT_STROKER_BORDER_RIGHT )
{
FT_StrokeBorder sborder = &stroker->borders[ border ];


if ( sborder->valid )

ft_stroke_border_export( sborder, outline

);
}
}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( void )

FT_Stroker_Export( FT_Stroker

stroker,

FT_Outline *outline

)
{
FT_Stroker_ExportBorder( stroker, FT_STROKER_BORDER_LEFT, outline

);

FT_Stroker_ExportBorder( stroker, FT_STROKER_BORDER_RIGHT, outline

);
}


/* documentation is in ftstroke.h */

/*
 *  The following is very similar to FT_Outline_Decompose, except
 *  that we do support opened paths, and do not scale the outline.
 */
FT_EXPORT_DEF( FT_Error )

FT_Stroker_ParseOutline( FT_Stroker

stroker,

FT_Outline *outline,
        FT_Bool

opened )
{
FT_Vector v_last;

FT_Vector v_control;

FT_Vector v_start;

FT_Vector *point;

FT_Vector *limit;

char *tags;

FT_Error error;

FT_Int n;         /* index of contour in outline     */
FT_UInt first;     /* index of first point in contour */
FT_Int tag;       /* current point's state           */


if ( !outline || !stroker )
return

FT_Err_Invalid_Argument;

FT_Stroker_Rewind( stroker );

first = 0;

for (

n = 0;

n < outline->

n_contours;

n++ )
{
FT_UInt last;  /* index of last point in contour */


last = outline->contours[ n ];

limit = outline->points + last;

/* skip empty points; we don't stroke these */
if ( last <= first )
{
first = last + 1;

continue;
}

v_start = outline->points[ first ];

v_last = outline->points[ last ];

v_control = v_start;

point = outline->points + first;

tags = outline->tags + first;

tag = FT_CURVE_TAG( tags[ 0 ] );

/* A contour cannot start with a cubic control point! */
if ( tag == FT_CURVE_TAG_CUBIC )
goto

Invalid_Outline;

/* check first point to determine origin */
if ( tag == FT_CURVE_TAG_CONIC )
{
/* First point is conic control.  Yes, this happens. */
if (

FT_CURVE_TAG( outline

->tags[last] ) == FT_CURVE_TAG_ON )
{
/* start at last point if it is on the curve */
v_start = v_last;

limit--;
}
else
{
/* if both first and last points are conic, */
/* start at their middle                    */
v_start.

x = ( v_start.x + v_last.x ) / 2;

v_start.

y = ( v_start.y + v_last.y ) / 2;

}
point--;
tags--;
}

error = FT_Stroker_BeginSubPath( stroker, &v_start, opened );

if ( error )
goto

Exit;

while ( point < limit )
{
point++;
tags++;

tag = FT_CURVE_TAG( tags[ 0 ] );

switch ( tag )
{
case FT_CURVE_TAG_ON:  /* emit a single line_to */
{
FT_Vector vec;


vec.

x = point->x;

vec.

y = point->y;

error = FT_Stroker_LineTo( stroker, &vec );

if ( error )
goto

Exit;

continue;
}

case FT_CURVE_TAG_CONIC:  /* consume conic arcs */
v_control.

x = point->x;

v_control.

y = point->y;

Do_Conic:
if ( point < limit )
{
FT_Vector vec;

FT_Vector v_middle;


point++;
tags++;

tag = FT_CURVE_TAG( tags[ 0 ] );

vec = point[ 0 ];

if ( tag == FT_CURVE_TAG_ON )
{
error = FT_Stroker_ConicTo( stroker, &v_control, &vec );

if ( error )
goto

Exit;

continue;
}

if ( tag != FT_CURVE_TAG_CONIC )
goto

Invalid_Outline;

v_middle.

x = ( v_control.x + vec.x ) / 2;

v_middle.

y = ( v_control.y + vec.y ) / 2;

error = FT_Stroker_ConicTo( stroker, &v_control, &v_middle );

if ( error )
goto

Exit;

v_control = vec;

goto

Do_Conic;

}

error = FT_Stroker_ConicTo( stroker, &v_control, &v_start );

goto

Close;

default:  /* FT_CURVE_TAG_CUBIC */
{
FT_Vector vec1, vec2;


if ( point + 1 > limit                             ||

FT_CURVE_TAG( tags[1] )

!= FT_CURVE_TAG_CUBIC )
goto

Invalid_Outline;

point += 2;
tags  += 2;

vec1 = point[ -2 ];

vec2 = point[ -1 ];

if ( point <= limit )
{
FT_Vector vec;


vec = point[ 0 ];

error = FT_Stroker_CubicTo( stroker, &vec1, &vec2, &vec );

if ( error )
goto

Exit;

continue;
}

error = FT_Stroker_CubicTo( stroker, &vec1, &vec2, &v_start );

goto

Close;

}
}
}

Close:
if ( error )
goto

Exit;

/* don't try to end the path if no segments have been generated */
if ( !stroker->first_point )
{
error = FT_Stroker_EndSubPath( stroker );

if ( error )
goto

Exit;

}

first = last + 1;

}

return

FT_Err_Ok;

Exit:
return

error;

Invalid_Outline:
return

FT_Err_Invalid_Outline;

}


/* declare an extern to access `ft_outline_glyph_class' globally     */
/* allocated  in `ftglyph.c', and use the FT_OUTLINE_GLYPH_CLASS_GET */
/* macro to access it when FT_CONFIG_OPTION_PIC is defined           */
#ifndef FT_CONFIG_OPTION_PIC

extern const FT_Glyph_Class ft_outline_glyph_class;

#endif

#include "basepic.h"


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_Error )

FT_Glyph_Stroke( FT_Glyph

*pglyph,

FT_Stroker stroker,
        FT_Bool

destroy )
{
FT_Error error = FT_Err_Invalid_Argument;

FT_Glyph glyph = NULL;

FT_Library library = stroker->library;

FT_UNUSED( library );


if ( pglyph == NULL )
goto

Exit;

glyph = *pglyph;

if ( glyph == NULL || glyph->clazz != FT_OUTLINE_GLYPH_CLASS_GET )
goto

Exit;

{
FT_Glyph copy;


error = FT_Glyph_Copy( glyph, &copy );

if ( error )
goto

Exit;

glyph = copy;

}

{
FT_OutlineGlyph oglyph = ( FT_OutlineGlyph ) glyph;

FT_Outline *outline = &oglyph->outline;

FT_UInt num_points, num_contours;


error = FT_Stroker_ParseOutline( stroker, outline, FALSE );

if ( error )
goto

Fail;

(void)

FT_Stroker_GetCounts( stroker,

&num_points, &num_contours );

FT_Outline_Done( glyph

->library, outline );

error = FT_Outline_New( glyph->library,
                        num_points, num_contours, outline );

if ( error )
goto

Fail;

outline->

n_points = 0;

outline->

n_contours = 0;

FT_Stroker_Export( stroker, outline

);
}

if ( destroy )

FT_Done_Glyph( *pglyph );

*

pglyph = glyph;

goto

Exit;

Fail:

FT_Done_Glyph( glyph );

glyph = NULL;

if ( !destroy )
*

pglyph = NULL;

Exit:
return

error;

}


/* documentation is in ftstroke.h */

FT_EXPORT_DEF( FT_Error )

FT_Glyph_StrokeBorder( FT_Glyph

*pglyph,

FT_Stroker stroker,
        FT_Bool

inside,

FT_Bool destroy

)
{
FT_Error error = FT_Err_Invalid_Argument;

FT_Glyph glyph = NULL;

FT_Library library = stroker->library;

FT_UNUSED( library );


if ( pglyph == NULL )
goto

Exit;

glyph = *pglyph;

if ( glyph == NULL || glyph->clazz != FT_OUTLINE_GLYPH_CLASS_GET )
goto

Exit;

{
FT_Glyph copy;


error = FT_Glyph_Copy( glyph, &copy );

if ( error )
goto

Exit;

glyph = copy;

}

{
FT_OutlineGlyph oglyph = ( FT_OutlineGlyph ) glyph;

FT_StrokerBorder border;

FT_Outline *outline = &oglyph->outline;

FT_UInt num_points, num_contours;


border = FT_Outline_GetOutsideBorder( outline );

if ( inside )
{
if ( border == FT_STROKER_BORDER_LEFT )

border = FT_STROKER_BORDER_RIGHT;

else

border = FT_STROKER_BORDER_LEFT;

}

error = FT_Stroker_ParseOutline( stroker, outline, FALSE );

if ( error )
goto

Fail;

(void)

FT_Stroker_GetBorderCounts( stroker, border,

&num_points, &num_contours );

FT_Outline_Done( glyph

->library, outline );

error = FT_Outline_New( glyph->library,
                        num_points,
                        num_contours,
                        outline );

if ( error )
goto

Fail;

outline->

n_points = 0;

outline->

n_contours = 0;

FT_Stroker_ExportBorder( stroker, border, outline

);
}

if ( destroy )

FT_Done_Glyph( *pglyph );

*

pglyph = glyph;

goto

Exit;

Fail:

FT_Done_Glyph( glyph );

glyph = NULL;

if ( !destroy )
*

pglyph = NULL;

Exit:
return

error;

}


/* END */
